Method to control an atmosphere between a body and a substrate

ABSTRACT

Systems to control an atmosphere about a substrate are described. The systems include a wall coupled to the substrate to create a resistance of the flow between different regions of the substrate.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

The present application is a continuation of U.S. Ser. No. 11/231,580filed on Sep. 21, 2005, which is incorporated by reference herein in itsentirety. U.S. Ser. No. 11/231,580 is related in subject matter to U.S.Pat. No. 7,316,554, which is incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION

The field of the invention relates generally to micro-fabricationtechniques. More particularly, the present invention is directed to asystem of controlling an atmosphere between a mold and a substrate.

Nano-fabrication involves the fabrication of very small structures,e.g., having features on the order of nano-meters or smaller. One areain which nano-fabrication has had a sizeable impact is in the processingof integrated circuits. As the semiconductor processing industrycontinues to strive for larger production yields while increasing thecircuits per unit area formed on a substrate, nano-fabrication becomesincreasingly important. Nano-fabrication provides greater processcontrol while allowing increased reduction of the minimum featuredimension of the structures formed. Other areas of development in whichnano-fabrication has been employed include biotechnology, opticaltechnology, mechanical systems and the like.

An exemplary nano-fabrication technique is commonly referred to asimprint lithography. Exemplary imprint lithography processes aredescribed in detail in numerous publications, such as U.S. patentapplication publication 2004/0065976 filed as U.S. patent applicationSer. No. 10/264,960, entitled, “Method and a Mold to Arrange Features ona Substrate to Replicate Features having Minimal DimensionalVariability”; U.S. patent application publication 2004/0065252 filed asU.S. patent application Ser. No. 10/264,926, entitled “Method of Forminga Layer on a Substrate to Facilitate Fabrication of MetrologyStandards”; and U.S. Pat. No. 6,936,194, entitled “Functional PatterningMaterial for Imprint Lithography Processes,” all of which are assignedto the assignee of the present invention.

The fundamental imprint lithography technique disclosed in each of theaforementioned United States patent application publications and UnitedStates patent includes formation of a relief pattern in a polymerizablelayer and transferring a pattern corresponding to the relief patterninto an underlying substrate. The substrate may be positioned upon amotion stage to obtain a desired position to facilitate patterningthereof. To that end, a template is employed spaced-apart from thesubstrate with a formable liquid present between the template and thesubstrate. The liquid is solidified to form a solidified layer that hasa pattern recorded therein that is conforming to a shape of the surfaceof the template in contact with the liquid. The template is thenseparated from the solidified layer such that the template and thesubstrate are spaced-apart. The substrate and the solidified layer arethen subjected to processes to transfer, into the substrate, a reliefimage that corresponds to the pattern in the solidified layer.

U.S. patent application publication 2005/0074512 filed as U.S. patentapplication Ser. No. 10/898,037 entitled “System for Creating aTurbulent Flow of Fluid between a Mold and a Substrate” describes asystem for introducing a flow of a fluid between a mold and a substrate.More specifically, the system includes a baffle coupled to a chuck, thebaffle having first and second apertures in communication with a fluidsupply to create a turbulent flow of the fluid between the mold and thesubstrate.

To that end, it may be desired to provide an improved system ofcontrolling the atmosphere between a mold and a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified side view of a lithographic system having wallscoupled to an imprint head;

FIG. 2 is a side view of a portion of the system shown in FIG. 1, withthe walls placed in a first position;

FIG. 3 is a side view of a portion of the system shown in FIG. 1, withthe walls placed in a second position;

FIG. 4 is a side view of a portion of the lithographic system shown inFIG. 1, with a template in contact with a material on a substrate; and

FIG. 5 is a side view of a portion of the lithographic system shown inFIG. 1, with the walls being positioned to expose a portion of anatmosphere between a template and a substrate to an ambient environment.

DETAILED DESCRIPTION OF THE INVENTION

A system 10 employed to form a relief pattern in a substrate 12 includesa stage 14 upon which substrate 12 is supported, and a template 16having a mold 18 with a patterning surface 20 thereon. In a furtherembodiment, substrate 12 may be coupled to a substrate chuck (notshown), the substrate chuck (not shown) being any chuck including, butnot limited to, vacuum and electromagnetic.

Template 16 and/or mold 18 may be formed from such materials includingbut not limited to, fused-silica, quartz, silicon, organic polymers,siloxane polymers, borosilicate glass, fluorocarbon polymers, metal, andhardened sapphire. As shown, patterning surface 20 comprises featuresdefined by a plurality of spaced-apart recessions 22 and protrusions 24.However, in a further embodiment, patterning surface 20 may besubstantially smooth and/or planar. The plurality of features ofpatterning surface 20 defines an original pattern that forms the basisof a pattern to be formed on substrate 12.

Template 16 may be coupled to an imprint head 26 to facilitate movementof template 16, and therefore, mold 18. In a further embodiment,template 16 may be coupled to a template chuck (not shown), the templatechuck (not shown) being any chuck including, but not limited to, vacuumand electromagnetic. A fluid dispense system 27 is coupled to beselectively placed in fluid communication with substrate 12 so as todeposit a polymerizable material 28 thereon. It should be understoodthat polymerizable material 28 may be deposited using any knowntechnique, e.g., spin-coating, dip coating, chemical vapor deposition(CVD), physical vapor deposition (PVD), and the like. In the presentexample, however, polymerizable material 28 is deposited as a pluralityof spaced-apart discrete droplets 30 on substrate 12.

A source 32 of energy 34 is coupled to direct energy 34 along a path 36.Imprint head 26 and stage 14 are configured to arrange mold 18 andsubstrate 12, respectively, to be in superimposition, and disposed inpath 36. Either imprint head 26, stage 14, or both vary a distancebetween mold 18 and substrate 12 to define a desired volume therebetweenthat is filled by polymerizable material 28.

Typically, polymerizable material 28 is disposed upon substrate 12before the desired volume is defined between mold 18 and substrate 12.However, polymerizable material 28 may fill the volume after the desiredvolume has been obtained. After the desired volume is filled withpolymerizable material 28, source 32 produces energy 34, which causespolymerizable material 28 to solidify and/or cross-link, forming apolymeric material conforming to the shape of a surface 38 of substrate12 and patterning surface 20 of mold 18. Control of this process isregulated by processor 40 that is in data communication with stage 14,imprint head 26, fluid dispense system 27, and source 32, operating on acomputer-readable program stored in memory 42.

System 10 further comprises a pair of conduits 44 a and 44 b. As shown,conduits 44 a and 44 b are coupled to imprint head 26; however, conduits44 a and 44 b may be coupled to any part of system 10, i.e., substrate12, stage 14, template 16, the substrate chuck (not shown), or thetemplate chuck (not shown). Further, system 10 may comprise any numberof conduits. Conduits 44 a and 44 b may be in fluid communication with apump system 46 via throughways 48. As shown, throughways 48 arecontained within imprint head 26. However, in a further embodiment,throughways 48 may be positioned anywhere throughout system 10 and maybe coupled to any part of system 10, i.e., substrate 12, stage 14,template 16, the substrate chuck (not shown), or the template chuck (notshown). Pump system 46 may be in communication with processor 40operating on memory 42 to control an introduction/evacuation of a fluid54 in an atmosphere 56 defined between mold 18 and droplets 30,described further below.

Further, system 10 comprises walls 50 coupled to imprint head 26. In afurther embodiment, walls 50 may be coupled to any part of system 10,i.e., substrate 12, stage 14, template 16, the substrate chuck (notshown), or the template chuck (not shown). Walls 50 may be positioned atan interface between first and second regions 58 and 60 of substrate 12,with first region 58 being in superimposition with mold 18 and droplets30. Further, walls 50 may substantially surround imprint head 26, andtherefore, atmosphere 56. However, for simplicity of illustration, walls50 are shown surrounding a portion of imprint head 26 and atmosphere 56.

Walls 50 may be in communication with a motor 52, with motor 52controlling a motion thereof. For simplicity of illustration, motor 52is shown as two separate bodies. Motor 52 may comprise a solenoidselected from a group of solenoids including but not limited to,electric, pneumatic, and hydraulic. Further, motor 52 may be employedwithout feedback. Motor 52 may be in communication with processor 40operating on memory 42.

As mentioned above, during imprinting, template 16 and therefore, mold18, are brought into proximity with substrate 12 before positioningpolymerizable material 28 in droplets 30 upon substrate 12.Specifically, template 16 is brought within hundreds of microns ofsubstrate 12, e.g., approximately 200 microns. It has been founddesirable to perform localized control of atmosphere 56 that isproximate to both template 16 and substrate 12. For example, to avoidthe deleterious effects of gases and/or gas pockets present inpolymerizable material 28 in droplets 30 and/or subsequently trapped ina patterned layer, described further below, formed from droplets 30, ithas been found beneficial to control desired properties of atmosphere 56and/or the pressure of atmosphere 56. More specifically, it may bedesired to control fluid 54 within atmosphere 56. To that end, a systemand a method to facilitate control of atmosphere 56 is described below.

Referring to FIG. 2, a portion of system 10 is shown. More specifically,mold 18 is shown spaced-apart from surface 38 of substrate 12 a firstdistance ‘d₁’. Distance ‘d₁’ may be on the order of hundreds of microns,i.e., approximately 200 to 300 microns. Walls 50 of system 10 are shownplaced in a first position spaced-apart a distance ‘d₂’ from surface 38of substrate 12. Distance ‘d₂’ may be on the order of tens of microns,i.e., approximately 50 microns.

Pump system 46 may introduce fluid 54 into atmosphere 56 throughthroughways 48 and conduits 44 a and 44 b. Fluid 54 may comprise a gasselected from a group of gases including, but not limited to, helium,hydrogen, nitrogen, carbon dioxide, and xenon. Fluid 54 may beintroduced into atmosphere 56 through conduits 44 a and 44 b employingany desired method. For example, fluid 54 may be introduced through bothconduits 44 a and 44 b concurrently, or sequentially pulsed through thesame, i.e., first fluid is introduced through conduit 44 a andsubsequently through conduit 44 b and then again through conduit 44 b,with the process being repeated for a desired time or during the entireimprinting process. Methods for introduction/evacuation of fluid 54through conduits 44 a and 44 b is disclosed in U.S. patent applicationpublication 2005/0072755 filed as U.S. patent application Ser. No.10/677,639 entitled “Single Phase Fluid Imprint Lithography Method,”which is incorporated by reference herein in its entirety. In anexample, conduits 44 a and 44 b may introduce fluid 54 within atmosphere56 at a flow rate of 9 liters/minute.

To that end, it may be desired to control atmosphere 56, and morespecifically, it may be desired to maintain fluid 54 within atmosphere56 preceding to and until contact between mold 18 and polymerizablematerial 28 in droplets 30. In a further embodiment, it may be desiredto maintain fluid 54 within atmosphere 56 prior to and subsequent tocontact between mold 18 and polymerizable material 28 in droplets 30. Inan example, it may be desired to have atmosphere 56 comprise more than a95% mass fraction of fluid 54 therein. To that end, walls 50 facilitatecontrol of atmosphere 56 by creating a flow resistance between first andsecond regions 58 and 60 of substrate 12. More specifically, asmentioned above, walls 50 are spaced-apart a distance ‘d₂’ from surface38 of substrate 12; and mold 18, in superimposition with polymerizablematerial 28 in droplets 30, is spaced-apart a distance ‘d₁’ from surface38 of substrate 12. Further, distance ‘d₁’ is substantially greater thandistance ‘d₂’. As a result, a greater resistance to a flow of fluid 54is established between walls 50 and surface 38 of substrate 12 thanbetween mold 18 and surface 38 of substrate 12; and thus, fluid 54 maytend to be maintained within atmosphere 56, which may be desired. For agiven flow rate of fluid 54 through conduits 44 a and 44 b and a givenvolume of atmosphere 56, the distance ‘d₂’ may be selected to achieve adesired resistance to the flow of fluid 54 between first and secondregions 58 and 60 of substrate 12.

However, as mentioned above, a desired volume is defined between mold 18and substrate 12 that is filled by polymerizable material 28 in droplets30. More specifically, imprint head 26 may position mold 18 such thatpolymerizable material 28 in droplets 30 are in contact therewith. As aresult, walls 50 may translate to minimize a probability of the samecontacting substrate 12 during a decrease in a magnitude of distance‘d₁’, and more specifically, during contact of mold 18 withpolymerizable material 28 in droplets 30. Contact of substrate 12 bywalls 50 may result in, inter alia, structural comprise of system 10,impedance of contact between mold 18 and droplets 30, misalignment ofmold 18 with respect to substrate 12, and damage to substrate 12 and/ormold 18, all of which are undesirable.

Referring to FIG. 3, to that end, walls 50 may translate in a firstdirection away from substrate 12. More specifically, motor 52 mayposition walls 50 such that the same are positioned a distance ‘d₃’ fromsurface 38 of substrate 12, with distance ‘d₃’ being greater thandistance ‘d₁’. Distance ‘d₃’ may be on the order of hundreds of microns.

Referring to FIG. 4, mold 18 is shown in mechanical contact withpolymerizable material 28, spreading droplets 30, shown in FIG. 1, so asto generate a contiguous formation 62 of polymerizable material 28 oversurface 38 of substrate 12. Template 16, and further, mold 18, maytranslate in a second direction towards substrate 12, with the seconddirection being opposite to the aforementioned first direction. In afurther embodiment, stage 14, and further, substrate 12 may translate ina third direction towards mold 18, with the third direction being in adirection substantially the same as the first direction. Furthermore,walls 50 may translate in the first direction concurrently orasynchronously with translation of mold 18 and/or substrate 12.

Referring to FIG. 1, in a preferred embodiment, fluid 54 may beintroduced into atmosphere 56 at any time prior to contact between mold18 and droplets 30. However, in a further embodiment, introduction offluid 54 into atmosphere 56 may be ceased at any time.

Referring to FIG. 5, in a preferred embodiment, it may be desired toexpose a portion of atmosphere 56, shown in FIG. 1, to an ambientenvironment to facilitate control of fluid 54 within atmosphere 56,shown in FIG. 1. To that end, walls 50 a and 50 b may be positioneddistance ‘d₂’ from surface 38 of substrate 12, as mentioned above.However, wall 50 c may be positioned a distance ‘d₄’ from surface 38 ofsubstrate 12. Distance ‘d₄’ may have a magnitude approximately between200 microns and 1 millimeter. As a result, atmosphere 56 may be exposedto an ambient environment. In a further embodiment, walls 50 maysubstantially surround imprint head 26, and thus atmosphere 56, forminga chamber (not shown). The chamber (not shown) may be completelyevacuated or pressurized.

Referring to FIG. 2, in a further embodiment, to increase a quantity offluid 54 disposed within atmosphere 56, distance ‘d₁’ may be increasedprior to contact of mold 18 with droplets 30. More specifically,distance ‘d₁’ may be on the order of millimeters, i.e., approximately 1millimeter.

The embodiments of the present invention described above are exemplary.Many changes and modifications may be made to the disclosure recitedabove, while remaining within the scope of the invention. Therefore, thescope of the invention should not be limited by the above description,but instead should be determined with reference to the appended claimsalong with their full scope of equivalents.

1. A system to control an atmosphere about a substrate, the systemcomprising: a template having a mold spaced-apart a distance from asurface of the substrate; a supply of fluid coupled to introduce a flowbetween the mold and the substrate; a substrate chuck supporting thesubstrate; and a wall coupled to the substrate chuck to create aresistance of the flow between first and second regions of thesubstrate, with a position of the wall being varied in response to adecrease in a magnitude of the distance.
 2. The system as recited inclaim 1 further including a plurality of walls coupled to the substratechuck.
 3. The system as recited in claim 1 wherein the supply of fluidfurther includes a conduit to introduce the fluid between the mold andthe substrate.
 4. The system as recited in claim 1 wherein the supply offluid further includes a plurality of conduits at differing locations tointroduce the fluid between the mold and the substrate.
 5. The system asrecited in claim 1 wherein the fluid is selected from a group of gasesincluding helium, hydrogen, nitrogen, carbon dioxide, and xenon.
 6. Thesystem as recited in claim 3 further including a pump system in fluidcommunication with the conduit.
 7. The system as recited in claim 1further including a motor in communication with the wall, with the motorbeing a solenoid selected from a group of solenoids comprising electric,pneumatic, and hydraulic.
 8. A system to control an atmosphere about asubstrate, the system comprising: a template having a mold spaced-aparta distance from a surface of the substrate; a supply of fluid coupled tointroduce a flow between the mold and the substrate; a substrate chucksupporting the substrate; and a wall coupled to the substrate chuck tocreate a resistance of the flow between first and second regions of thesubstrate, with a position of the wall being varied to minimize aprobability of contact between the wall and the template when amagnitude of the distance is decreased.
 9. The system as recited inclaim 8 further including a plurality of walls coupled to the substratechuck.
 10. The system as recited in claim 8 wherein the supply of fluidfurther includes a conduit to introduce the fluid between the mold andthe substrate.
 11. The system as recited in claim 8 wherein the supplyof fluid further includes a plurality of conduits at differing locationsto introduce the fluid between the mold and the substrate.
 12. Thesystem as recited in claim 11 further including a pump system in fluidcommunication with the conduit.
 13. The system as recited in claim 8wherein the fluid is selected from a group of gases including helium,hydrogen, nitrogen, carbon dioxide, and xenon.
 14. The system as recitedin claim 8 further including a motor in communication with the wall,with the motor being a solenoid selected from a group of solenoidscomprising electric, pneumatic, and hydraulic.
 15. A system to controlan atmosphere about a substrate, the system comprising: a templatehaving a mold spaced-apart from a surface of the substrate a firstdistance; a conduit in fluid communication with a pump system coupled tointroduce a flow between the mold and the substrate; a substrate chucksupporting the substrate; and a wall coupled to the substrate chuck tocreate a resistance to the flow between first and second regions of thesubstrate to control the atmosphere about the first region, the wallpositioned at a second distance, wherein the first distance issubstantially greater than the second distance.
 16. The system of claim15, wherein the second distance is between approximately 10 μm-100 μm.17. The system as recited in claim 15, further including a plurality ofwalls coupled to the substrate chuck.
 18. The system as recited in claim15, further including a plurality of conduits at differing locations.19. The system as recited in claim 15, wherein the fluid is selectedfrom a group of gases including helium, hydrogen, nitrogen, carbondioxide, and xenon.
 20. The system as recited in claim 15, furtherincluding a motor in communication with the wall, with the motor being asolenoid selected from a group of solenoids comprising electric,pneumatic, and hydraulic.